Messages in this thread | | | Date | Wed, 26 May 1999 22:08:39 +0200 (MEST) | From | Finn Arne Gangstad <> | Subject | Re: [patch] checksum P6 asm buffer overflow fix + 686 improvements |
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On Mon, 24 May 1999, Andrea Arcangeli wrote:
> In the 686 asm of csum_partial there is an andl done on a memory address > that as best will contains only 3 valid bytes. As far as the four byte is > in the 4mbyte pagetable with the kernel there is no problem (since the > four byte is then ignored by masking) but in the unlikely case that the > first one/two/three bytes are the last bytes of a vmalloced area, then > accessing the second/third/four byte will generate an Oops.
The address is aligned to 4 before it is possible to hit that instruction, and I don't see how reading 4 bytes aligned to 4 can fault.
- Finn Arne
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